When digital camera users take photographs that will eventually make up a panorama, they can have the most effective results if the photographs are taken with an optimal amount of overlap and reasonably good alignment to begin with. Current generation cameras attempt to help the user with this, but they are only minimally effective.
For panoramas, if the sequence of photographs are not aligned well along the horizon, the final panorama is limited in the vertical direction by the top of the lowest photograph of the series that is taken, and the bottom of the highest photograph that is taken. Thus, the best outcome results when each photo is aligned well with the others horizontally.
Any time that stitching is employed between photographs, the best matching and results occur when there is enough overlap between the photographs to accurately match features and also to avoid image distortion that can occur at the edges of the lens. This optimal amount of overlap varies from camera to camera, but manufacturers can specify the amount for each.
Alignment across sequential photos, side-to-side, is not too bad (unassisted) because every photograph only has one side overlap that the user needs to remember. However, to create composite photographs or more complex panoramas (360 degrees or perhaps with two passes, with one vertically higher than the other), each photograph may end up with multiple overlapping images. This is much harder to align well, even using a tripod.
The present inventor believes that the process of taking composite photographs does not have any good support in current generation cameras. There needs to be some guidance to help the user take a zigzag series of photographs in the best order and with enough overlap on two sides to make image stitching successful.
The only support for panoramas in digital cameras that the present inventor is aware of are lines that the camera can display on a display screen. The user is supposed to mentally keep track of what part of the image was at the line on one photograph, then move that part of the image over to the line on the opposite side. The camera does not do anything specific, the user has to remember what was there when the picture was taken. As mentioned before, this is reasonable for a simple side-to-side panorama, however, it does not work for more complex compositions.
Analog cameras make a panorama effect by cropping the top and bottom of the image and constraining the user to use a wide angle mode. However, the entire image is still placed on only one film exposure. This is a very limited and awkward method of creating panoramas.
U.S. Pat. No. 6,411,742 issued to Peterson, entitled “Merging images to form a panoramic image” discloses “a method of blending images of segments of a view. The method includes determining the position of a second segment of the view represented by a second image relative to a first segment of the view represented by a first image, dividing the second image into a first section and a second section, based on the determined positions, drawing the first image on a canvas, and drawing the first section of the second image on the canvas at the determined position so that a portion of the first section masks out a portion of the first image.” [see Summary]
U.S. Pat. No. 6,064,399 issued to Teo, entitled “Method and system for panel alignment in panoramas” discloses a “method and system for constructing a panoramic image including the steps of applying panoramic curvature to at least one image, thereby to create a panoramic background embedding in the panoramic background an additional image having a geometry other than that of the panoramic curvature thereby to provide a composite panoramic image containing an embedded image corresponding to the additional image and whose geometry matches that of the panoramic background.” [see Abstract]
U.S. Pat. No. 6,323,858 issued to Gilbert et al., entitled “System for digitally capturing and recording panoramic movies” discloses a “digital system for capturing and storing panoramic images using progressive scan (that is, non interlaced) technology. The system includes a digital image input device and an associated control computer. . . . The image input device has six lenses positioned on the six faces of a cube. While the image input system can have other lens configurations, the use of six lenses in a cubic configuration is optimal for a system that is used to capture a spherical panorama.” [see Abstract]